The present invention relates to systems and methods for using a cartridge case as a tool to install or remove firearm accessories such as a barrel attachment. The barrel attachment includes a coupling section for attaching the barrel attachment to a firearm barrel. The barrel attachment also includes a rim channel for engaging a portion of the rim of a cartridge case. This rim channel provides mechanical leverage by enabling a user to apply force on the engaged cartridge case to rotate the barrel attachment around a bore axis of the firearm barrel. In some embodiments, the rim channel is an integral portion of a cartridge rim slot machined into the exterior part of the barrel attachment. Ideally, the rim channel includes a curved portion to increase the load-bearing contact area. The rim channel can also be adapted to accept different case rim sizes. Multiple rim slots can be machined into the barrel attachment, allowing the user to spread out the forces amongst multiple cartridge cases. The contact area between the rim of the cartridge case and the barrel attachment can be further increased by sliding a half-moon insert into the rim slot.